A variable force is a force that changes in magnitude or direction over time. Unlike a constant force, which remains the same, a variable force can fluctuate due to different factors, such as the position of an object or external influences. For example, the gravitational force acting on an object varies with its distance from the Earth. One common example of a variable force is the spring force in a spring. When a spring is compressed or stretched, the force it exerts changes according to Hooke's Law, which states that the force is proportional to the displacement from its equilibrium position. This means that the more you stretch or compress the spring, the greater the force it exerts.